Hydrostatic brake



HYDROSTATIC BRAKE Filed Jan. 1 1940 a0" 72 72 A f 7578 68 4 74 44 .5 as90 F? z 856 44 2 Sheets-Sheet l Oct. 28, 1941. c. SAUZEDDE 2,260,340

HYDROSTATIC BRAKE Filed Jan. 18, 1940 2 Sheets-Sheet 2 Patented Oct. 28,1941 HYDROSTATIC BRAKE Claude Sauzedde, Detroit, Mich., assignor toDetroit Hydrostatic Brake Corporation, Detroit, Mich a corporation ofMichigan Application January 18, 1940, Serial N 0. 314,500

6 Claims.

This invention relates, in general, to vehicle brakes of the hydrostatictype and, in particular, to that part of the braking system residing atthe wheel.

One of the objects of the present invention is to provide a new andimproved vehicle brake of the hydrostatic type which operates with lesseffort and greater efliciency than heretofore.

Another object is to provide a new and improved vehicle brake whichrequires adjustments less frequently and which, when adjustments arenecessary, may be adjusted more easily, readily and efiectively thanheretofore.

Another object is to provide in a hydrostatic braking system a new andimproved fluid sealing arrangement at the wheel portion of said systemwhich is capable of withstanding higher fluid pressures and whichpermits the wheel piston to react more strictly in accordance with theactuation of the compression piston than heretofore.

Another object is to provide in a hydrostatic braking system a new andimproved arrangement for sealing the braking fluid at the wheel portionof said system which is not only less expensive and more effective thanheretofore but which presents an unyielding surface to the pressurecreated for the braking operation so as to eliminate any power losswhatsoever in the transmission of said pressure beyond said surface.

Other objects and advantages of the invention will become readilyapparent from a reference to the following specification taken inconjunction with the accompanying drawings of which there are two (2)sheets and wherein:

Figure 1 is a sectional view through the wheel section and to a brakingmechanism employing two units per wheel, it is to be clearly understoodthat such mechanism may be made readily and equally as applicable to therear wheel of the vehicle or to a braking surface having a cross sectionother than frusto-conical, and it may comprise more or less than twounits per wheel.

Such variations are contemplated and, it is believed, will reside withinthe herein inventive scope because they will require, in View of theenlightenment offered by the herein disclosure, the exercise of meremechanical skill in their employment. l I

As is usual in any wheel brake structure,the structure shown in the,figures comprises anonrotatable section, generally indicated at H), anda rotatable section, generally indicated, at I'2. The brake itself andits support constitute, as is usual, part of the non-rotatable sectionl0, and, since it has been optionally chosen to illustrate theparticular adaptation of the structure l0l2 to one of the frontwheels-of a vehicle, as distinguished from a rear wheel; thereof, thesupport for the wheel also constitutes part .of said section l0. i

The non-rotatable section ID of the wheel brake structure I 0l2comprises, in part, an axle [4 which is integral, as usual, with theWheel supporting portion [6 of the steering mechanism (not showncompletely) was to respond in accordance with the operators manipulationof said mechanism to direct the course of the vehicle. I

The rotatable section I2 of the wheel brake structure |0l2 comprises, inpart, a sectionally constructed hub consisting of an inner, cylindricalportion l8 and an outer, radially. outwardly extending portion 20, saidportion 20 being annular and carried by the outer end of said portion I8for rotation therewith as well, preferably, as for selective separationtherefrom to enable tire changing, inspection, etc., without thenecessity of removing both of said portions unitarily; The hub portionI8 is concentrically carried about the axle l4, through the use ofsuitable bearings and thrust members, for rotation relatively theretowithout axial movement therealong, and to the outer end of said portionthere is removably secured a hub cap 22. On the other hand, the hubportion 20 integrally carries at its periphery an annular tire carryingrim 24 (the tire not being shown) for rotation with the unit I8--20-22about the axis of the axle l4.

Referring again to the hub portion I8, said portion has fixed thereto,either removably or permanently and for rotation therewith, an annulardrum 26 which resides within the space defined by the hub portion 20 andextends outwardly from said portion [8 in successively radial anddiagonal directions to provide therewithin, with respect to the axis ofrotation of said drum, a

, able section frusto-conical braking surface 28. The outer end of thediagonal section of the drum 26 has integral therewith a relativelyshort cylindrical.

section 36, there being provided an annular, radially extending flange32 between said diagonal and cylindrical sections and another suchflange 34 provided at the opposite end of said section 30. annularlyflanged end 36 of another annular drum 38 Which provides, with respectto the axis of rotation of the rotatable section l2 of the wheel brakestructure, another frusto-conical braking surface 40, said drum 38 andthe drum 26 being secured together for unitary rotation by means of, aplurality of annularly spacedf belts or rivets. 42

Cooperable-with the flange 34 is the passing through and interconnectingthe flanged j portions 32, 34 and 36 of said drums. The end of the drum38 opposite its bolted end is absolutely free so that the rotatable unitI2, which consists in themain of the integrated elements I8,

26 and 38, together with the stationary or nonrotatable unit l0,which-consists in the main of.

the integrated elements l4, l6,the brake itself and its support (thelatter two of which are to be described), comprise a wheelbrakestructure of in use.

28' and ,40 comprise a single braking surface of frusto-c'onical crosssection, but it is to be re membered that such a showing is purelyillustratatable drum '38 and telescopically about said axle intoconfinement within the space or chamher-defined between said axle andthe braking surfaces 28 and 40. The spider 44 is integrally formed witha pair of diametrically spaced, cylinder-forming portions 46 the axes ofthe cylinders 48 of which. are co-aligned, normal to the axis of. wheelrotation (the axis of axle I4) and symmetrical. with respect .to orcentrally of the braking'surfaces 28 and 48. Each of the cy inders 48 isclosed at its inner radial end by means of the spider 44 itself and eachcarries, a

for reciprocation therein and relatively thereto,

a. pistorr 58 the head of which is cooperable with the portion. of saidspider closing said cylinder 1 end when said piston is'in. retractedposition.

Each of the pistons 50 is integrally provided with v a. stem 52 whichprojects outwardly of the respective cylinder 48 and is knurled,serrated or 3 notched, as, at '54, at its outerend so as to cooperatewith a complementarily knurled, serrated or notched end 56 of. athreaded stem 58 which is threadedlycarried in a threaded openingproderside of a brake shoe unit 62 for integrating the twofrusto-conically arranged shoes thereof. The two shoes of each unit 62are arcuate and the stem 58 which is adjustably connected to therespective bridge member6ll thereof is centered with. respect to thelatter as well as to said shoes so that any force exerted on therespective unit 62- through. the respective unit 50-52-58 will bedistributed equally over'the braking surfaces of the semi-floating type,a-type which is at present It is seen in Fig. 1 particularly that therotatable drums 26 and 38 comprise a single brake drum unit and thattheir braking surfaces said shoes and, resultantly, over the brakingsurfaces 28 and 40 of the drums 26 and 38.

The radially movable units 58-52-58-66-62 (each of which is separablyinterconnected at 54-56) are held in normally retracted position bymeans of a pair of springs 64 which resiliently interconnect said unitsand oppose their protraction.

The head of each of the pistons til is integrally formed with an annularskirt 66 which extends concentrically with respect to and in thedirection of its respective stem 52. Arranged between the outercylindrical wall of each of the skirts 66 and the wall of the respectivecylinder 48, in tightly fitting engagement with the latter, is acylinder-forming member 68 the formed cylinder (8 of which is slightlygreater in diameter than the outer diameter of said respective skirt,each of said members 68 being stationarily secured in place in itsrespective cylinder 48 by means of bolts 12 threadedly lodged in thespider 44. For reasons which will presently appear, the inner end ofeach of the members 68, when said member is in fixed position withrespect to the spider 44, is slightly spaced from that portion of saidspider which provides the base of the concentric cylinders 48 and 70.

Each of the stationary members 68, inaddition to providing the cylinder18, is formed at its outer end to close said cylinder, there beingprovided, however, an opening 14 through said end in which is freelyreceived the respective stem 52 and part of the abutting stem 58, thepart of said stem 58 received in said opening 1-4 being reduced indiameter and preferably un-threaded so as to enable the unit 62-68-58 tomove in the directionof theaxis of wheel rotation (for self-alignment ofthe shoes with respect to their drums) relatively to the non-axiallymovable unit 68-52-50 along the respective surface 54-56. of each of theunits 62-60-58-5'2-50 relatively to the respective member 66 and withoutrotation, thewall of each of the openings 14 is formed with akeyway 16extending in the direction of the axis of said opening and receiving akey 18 integrallyformcd on the periphery of the respective stem 52.

The outer end of each of the cylinder-forming cap members 68 isintegrally provided with a pair of prongs 88 which are arranged onopposite sides of the opening in the respective bridge vided therefor ina bridge-member 68 on the unmember 66 receiving the stem 58 and extendinto openings 82 provided therefor in said member, said prongscooperating with said openings 82 to permit the aforementioned axialmovement of the respective unit 62-68-58 relatively to the respectiveunit 68-52-58 but to prevent any movement of either of said units in adirection normal to said axial direction, that is, in the direction ofwheel rotation.

Referring to the enlarged view in Fig. 3, it will be noted that theelongated space of annular cross section existing between the outercylindrical wall of the piston skirt 66 and the innner cylindrical wallof the cap member 68 is filled with an elastic, cylindrical member 84the extremity of which adjacent the base of the cylinder 48 beingoutwardly flanged, as at 86, and the opposite extremity of which beingin wardly flanged, as at 88, said flange 86 overlying the inner end ofsaid cap member and said flange 88 overlying the end of said skirt,Bonderized or otherwise cemented to the end and side walls of the flange86 is a flanged, annular, metallic re- For enabling unitary, radialmovement enforcing ring 90, the end and side walls of the other flange88 also having Similarly secured thereto another such ring 90. Inassembly, a metallic, annular gasket 92, such as aluminum or otherrelatively soft material, having an outer diameter substantially similarto the diameter of the cylinder 48, is placed on the base of saidcylinder and the unit 90-8490 is then arranged over the skirt 66, therebeing provided, if desired, another gasket 94, similar to said gasket 92except for its outer diameter being sub stantially similar to the outerdiameter of said skirt rather than to that of said gasket 92,between theend of said skirt and the adjacent ends of the ring 90 and flange 88.Another gasket 90, similar to the gaskets 92 and 94 except for its outerdiameter being substantially similar to the diameter of the cylinder Irather than to that of said gasket 92 or to that of said gasket 94, isplaced over the end of the ring 90 opposite the end carrying said gasket94, and an annular, externally threaded, outwardly flanged nut 98 isthen screwed into the threaded, inner wall of the skirt 66 and securelytightened against said gasket 96 for unifying the elements 50-66, 84-90,94, 96 and 98. Finally, the cap member 68 is inserted between thecylinder wall 48 and the outer wall of the elastic member 84 andtightened in place by means of the bolts I2, it being seen that theinner end of said member 68 abuts the ring 90 and flange 88 and unifiesthe elements 44, 92, 84-90 and 68.

Referring to Fig. 2, the pistons 50 at each wheel are intercommunicatedby means of fluid passageways I80 and I02 formed in the spider 44 thelatter of which passageways is in communication with the manuallyoperated compressor (not shown) in the fluid system whereby said pistonsare protracted simultaneously upon the actuation of said compressor andretract by the springs 64 while said compressor is at rest. When thefluid system compressor is actuated, fluid under pressure enters each ofthe cylinders 48 and reacts upon the piston 50 therewithin, said fluidbeing confined behind said piston by means of the sealing unit9290-8490-96 or the unit 92-9084--9096-94. Protraction of the piston 50,to interengage the shoes and drums, elongates the elastic member 84, theflanged end 80 remaining stationary and the flanged end 88 moving withsaid piston. This sealing unit at each wheel cylinder assembly isleak-proof because there are little or no stresses applied to any of itselements so that extremely high fluid pressures may be employed inbraking. The fluid pressure is reactive in its entirety upon themetallic faces of the pistons 50 so that all is expended in protractingsaid pistons rather than having some spent, as has been customary, inthe give of, say, a rubber wall lying over each of said faces in thepath of said fluid. The construction and assembly of the elements of thesealing unit are obviously simple.

Referring lastly to the adjustability of the clearances between theshoes and their drums, the outer end I 04 of each of the stems 58extends beyond the respective supporting member 60, between the twoshoes of the respective unit 62, and is formed thereat with a polygonalcross section. The cylindrical section 30 of the drum 26 is formed witha plurality of spaced openings I08 which, at certain positions of saiddrum, register with the stem ends I04 for providing access to thelatter. In the vicinity of each of the openings I00 the ribs or flanges34 and 36 are flattened, as at I08, so that a wrench IIO may be insertedover either of the stem ends I04 from the inner side of the wheel andturned so as to move the respective shoe unit 62 toward or away from thebraking surface 2840. The knurled end 56 of the stem 58 being adjustedrides over the knurled end 54'of the non-rotatable stem 52, the unit6260 moves along said stem 58 in the direction intended by the turningof the wrench H0, and said knurled ends after the adjustment serve toprevent inadvertent turning of said stem 58.

Although the invention has been described with some detail it is notintended that such description be definitive of the limits of theinventive idea. The right is reserved to make such changes in thedetails of construction and arrangement of parts as will fall within thepurview of the at tached claims.

I claim.

1. In a hydrostatic braking mechanism having a rotatable brake drum anda non-rotatable braking member for and cooperable with the drum andcomprising, a non-rotatable support defining a cylinder in communicationwith a source of fluid pressure, a piston reciprocably mounted in saidcylinder and operatively connected to the braking member for unitarymovement therewith responsive to said pressure, a cylindrical member offlexible material arranged between said piston and the wall of saidcylinder and having its two ends radially flanged in oppositedirections, an annular reenforcing member permanently fixed to each ofsaid flanged ends of said flexible member, means arranged between saidflexible member and said cylinder wall and cooperable with one of saidreenforcing members for stationarily sealing the respective end of saidflexible member to the base of said cylinder, and means cooperable withthe other of said reenforcing members for sealing the respective end ofsaid flexible member to said piston for movement therewith.

2. In a hydrostatic braking mechanism having a rotatable brake drum anda non-rotatable braking member for and cooperable with the drum andcomprising, a non-rotatable support defining a cylinder in communicationwith a sourceof fluid pressure, a piston reciprocably mounted in saidcylinder and operatively connected ,to the braking member for unitarymovement therewith responsive to said pressure, a cylindrical member offlexible material arranged between said piston and the wall of saidcylinder and having its two ends radially flanged in oppositedirections, an annular reenforcing member permanently fixed to each ofsaid flanged ends of said flexible member, means arranged between saidflexible member and said cylinder wall and cooperablewith one of saidreenforcing members for stationarily sealing the respective end of saidflexible member to the base of said cylinder, means cooperable with theother of said reenforcing members for sealing the respective end of saidflexible member to said piston for movement therewith, an annular gasketarranged between said cylinder base and the reenforcing member thereat,and another annular gasket arranged between said second mentioned meansand the reenforcing member thereat.

3. In a hydrostatic braking mechanism having I reciprocation relativelythereto and operatively connected to the braking member for unitarilymoving the latter therewith in response to said pressure, said pistonbeing integrally formed with an annular skirt portion extending inconcentric and parallel relationship with respect to the wall of saidcylinder, a stationary guide member for the braking member and having anannular extension protruding into position between said cylinder walland the outer wall of said skirt portion, an annular clamping memberfixedly secured to the inner wall of said skirt portion for movementtherewith and overlying the end thereof, and a flexible, cylindricalsealing member arranged between the inner wall of said extension andsaidouter wall of said skirt portion and havingone of its ends fixedlysealed between the base of said cylinder and the end of said extensionand the other of its ends fixedly sealedbetween said clamping member andsaid end of said skirt portion.

4. In a hydrostatic braking mechanism having a'rotatable brake drum anda non-rotatable braking member for and cooperable with the drum andcomprising, a stationary support defining a cylinder in communicationwith a source of fluid pressure, a piston mounted in said cylinder forreciprocation relatively thereto and operatively connected to thebraking member for unitarily moving the latter therewith in response tosaid pressure, said piston being integrally formed with an annular skirtportion extending in concentric and parallel relationship with respectto the wall ofsaid cylinder, a stationary guide member for the brakingmember and having an annular extension protruding into position betweensaid cylinder wall and the outer wall of said skirt portion, an annularclamping member fixedly secured to the inner wall of said skirt portionfor movement therewith and overlying the end thereof, a flexible,cylindrical sealing member arranged between the inner wall of saidextension and said outer wall of said skirt portion and having its endsflanged in opposite directions so that one of said flanged ends residesbetween the base of said cylinder and the end of said extension and theother of said flanged ends resides between said clamping member and saidend of said skirt portion, and an annular, metallic reenforcing membersecured to each of said flanged endsv for providing inflexible spacingmeans between said cylinder base and said extension end and between saidclamping member and said skirt portion end.

5.- In a hydrostatic braking mechanism having a, rotatable brake drumand a non-rotatable brak ing member for and cooperable, with the drumand comprising, a stationary support defining a cylinder incommunication with a source of fluid pressure, apiston mounted in saidcylinder for reciprocation relatively thereto and operatively connectedto the braking member for unitarily moving the latter therewith inresponse to said pressure, said piston being integrally formed with anannular skirt portion extending in concentric and parallel relationshipwith respect to the wall of said cylinder, a stationary guide member forthe braking member and having an annular extension protruding intoposition between said cylinder wall and the outer wall of said skirtportion, an annular clamping member fixedly secured to the inner wall ofsaid skirt portion for movement therewith and overlying the end thereof,a flexible, cylindrical sealing member arranged between the inner wallof said extension and said outer wall of said skirt portion and havingone of its ends fixedly sealed between the base of said cylinder andtheend of said extension and the other of its ends fixedly sealed betweensaid clamping member and said end of said skirt portion, and a pair ofannular gaskets arranged one between said cylinder base and therespective end of said sealing member and the other between saidclamping member and the respective end of said sealing member.

6. In a hydrostatic braking mechanism having a rotatable brake drum anda non-rotatable braking member for and lcooperable with the drum andcomprising, a stationary support defining a cylinder in communicationwith a source of fluid pressure, a piston mounted in said cylinder forreciprocation relatively thereto and operatively connected to thebraking member for unitarily moving the latter therewith in response tosaid pressure, said piston being integrally formed with an annular skirtportion extending in concentric and parallel relationship with respectto the wall of said cylinder, a stationary guide member for the brakingmember and having an annular extension protruding into position betweensaid cylinder wall and the outer wall of said skirt portion, an annularclamping member fixedly securedto the inner wall of said skirt portionfor movement therewith and overlying the end thereof, a flexible,cylindrical sealing member arranged between the inner wall of saidextension and said outer wall of said skirt portion and havingits endsflanged in opposite directions so that one of said flanged ends residesbetween the base of said cylinder and the end of said extension and theother of said flanged ends resides between said clamping member and saidend of said skirt portion, an annular, metallic reenforcing membersecured to each of said flanged ends for providing inflexible spacingmeans between said cylinder base and said extension end and-between saidclamping member and said skirt portion end, and a pair of annulargaskets arranged one between saidcylinder base and one of saidreenforcing' members and the other between said clamping member and theother of said reenforcing members.

I CLAUDE SAUZEDDE.

